Tech

Video Converter Online: Convert Any Video Free

Convert MOV, MKV, AVI, WebM and more to MP4 or GIF online, free, with no download. Learn which video format to pick and the settings that actually matter.

October 22, 2026 · 5 min read · RunConvert Team

You shouldn't need to install anything to change a video's format. Yet a lot of "online" video converters work like a free sample: they convert the first minute, or add a watermark, then suggest you download their desktop app to finish the job. If you came here for a video converter that works entirely in your browser, from upload to download, this guide is for you.

We'll cover how to convert a video online, which output format to choose, and the handful of settings worth knowing about.

Convert a Video Online in Three Steps

Open the right converter. Go to the video converter and choose your output format, or open a direct pair like MOV to MP4 or MKV to MP4.
Add your video. Drag the file in or browse for it. Files up to 1 GB are accepted, so most phone and screen recordings fit easily.
Download the converted file. Processing starts right after the upload, and the result appears on the same page. There's no email link to wait for and no app to install.

That's the whole process. No account is required, nothing is watermarked, and the uploaded video is deleted automatically after conversion.

Which Video Format Should You Choose?

Video formats are really two things stacked together. The container (MP4, MOV, MKV, WebM) is the box. The codec (H.264, H.265/HEVC, VP9, AV1) is how the picture inside the box is compressed. Compatibility problems almost always come from one of the two.

When in doubt, choose MP4 with H.264. It plays on practically everything: iPhones, Android phones, Windows and Mac, smart TVs, every major browser, and editing apps from CapCut to Premiere.

Here's when other formats make sense:

Format	Best for	Watch out for
MP4	Sharing, uploading, playing anywhere	Nothing, really. It's the safe default
MOV	Editing on a Mac in Final Cut or iMovie	Some Windows apps and TVs won't play it
MKV	Keeping multiple audio tracks and subtitles	Many phones and editors don't support it
WebM	Embedding video on websites	Older iPhones and some editors struggle
AVI / WMV	Very old software that requires them	Large files, dated codecs
GIF	Short silent loops for chat or docs	Huge files, only 256 colours

The conversions people search for most:

MOV to MP4: iPhone and Mac recordings that won't play on Windows. See our guide on MOV vs MP4.
MKV to MP4: downloaded or recorded MKV files that phones and editors reject. Step by step: how to convert MKV to MP4.
WebM to MP4: browser screen recordings and web videos.
AVI to MP4: shrinking and modernising old camcorder or archive footage.
MP4 to GIF: a short clip for Slack, Discord or a README.
MP4 to MP3: just the audio, for a podcast, lecture or song.

Settings That Actually Matter

Most of the time the defaults are right and you can ignore the settings panel. When you do need control, these are the options worth understanding:

Resolution. Dropping from 4K to 1080p, or from 1080p to 720p, is the single biggest way to make a video smaller. On a phone screen, 720p and 1080p look almost the same.

Quality (CRF). Constant quality lets the encoder spend more data on complex scenes and less on static ones. Lower numbers mean higher quality and bigger files. For H.264, around 23 is the usual default, 18 is close to visually lossless, and 28 is noticeably smaller.

Video codec. H.264 for compatibility, H.265 (HEVC) for smaller files at the same quality, and AV1 for the smallest files on modern devices. If the source already uses a codec the target container supports, choosing copy skips re-encoding entirely. The conversion is then nearly instant and loses no quality.

Trim. Set a start and end time to keep only the part you need. That's useful before converting a long recording to GIF or MP3.

Remove audio. Handy for background loops or silent social clips, and it shaves a little off the file size.

If your goal is a smaller file rather than a different format, see our step-by-step guide to compressing video online without losing quality.

Why Not Just Use a Desktop App?

Desktop tools like HandBrake are excellent, and if you convert video every day they're worth learning. For occasional jobs, an online video converter wins on convenience:

Nothing to install or update. It works the same on Windows, Mac, Linux and Chromebooks.
No need for a powerful computer. The conversion runs on our servers, so an old laptop or a phone is fine.
Batch-friendly. Add several files and convert them in one go.
Works on a locked-down work machine where you can't install software.

Common Problems (and Fixes)

"The converted video has no sound." Some sources use audio codecs the output container doesn't support. Converting to MP4 re-encodes the audio to AAC, which plays everywhere. Also check that "remove audio" isn't switched on.

"The video is sideways." Phones store rotation as a flag rather than rotating the pixels. Use the rotate option and set it to auto or the correct angle.

"My MP4 still won't play on Windows." It's probably H.265/HEVC inside the MP4. Windows needs an extra codec for HEVC, so convert again with H.264 as the video codec.

"The file got bigger." That happens when you convert a heavily compressed video into a less efficient format, or raise the quality. Pick MP4 and leave quality on the default.

Convert Your Video Now

You don't need software, an account or a powerful computer to change a video's format. Open the video converter, drop your file in, and download an MP4 that plays everywhere. If you need audio only, the audio converter takes video files too.